The present application for a Patent of Invention relates, as indicated in its title, to "AN IMPROVED ANTI-PINCHING SYSTEM BASED ON MODIFICATION OF THE LIGHT CONDUCTIVITY OF AN OPTICAL FIBRE FOR AUTOMATIC CAR WINDOWS", whose new characteristics of construction, form and design fulfil with maximum reliability and efficacy the purpose for which it has specifically been designed.
The invention relates more specifically to the design of a new anti-pinching system using a light transmission means to detect obstacles between the perimeter of the car window and the frame of the door and of said window.
A plurality of systems exist on the market, and may therefore be regarded as prior art, which are capable of detecting an obstacle when a car window ascends in its frame in response to pressure exerted by the user on the window control button.
Said systems which may regarded as prior art may be divided into two broad groups, direct systems and indirect systems. The first thereof consist of sensors which, owing to their sensitivity, permit direct detection of the obstacle and send the appropriate signal to the electric motor whose role it is to actuate the various components involved in raising the window in such a way that the latter is stopped and its operation is reversed, such that it descends.
The indirect systems act in the normal manner on the motor and analyse the operation thereof in such a way that, when the window encounters an obstacle, a variation is produced in the current circulating through the electric motor or a modification is produced in the speed of rotation thereof, which is detected by the appropriate sensors incorporated in the electric motor. That is to say, it is through this variation in current or speed that the system detects the presence of an obstacle between the window and its frame, causing the motor to stop and reverse its direction of rotation.
Although the above systems represent considerable progress with respect to early arrangements which did not provide said anti-pinching and obstacle-detection systems, they exhibit severe limitations since they are subject to frequent breakdowns and in some cases they interpret modifications in the environment in which the window is displaced as obstacles, for example hardening of the guideways or the rubber seals disposed in the door frame in many cases causes an increase in the resistance encountered by the window as it ascends in the frame, which the sensors interpret as the unexpected presence of obstacles, such that they stop the motor and reverse its rotation, obliging the user to return to the dealer so that the problem can be solved by reprogramming of the various systems so as to prevent said disadvantages.
On another technical plane, the above-described systems are in many cases incapable of sensing pinching at the sides, that is to say not only pinching which occurs between the upper part or edge of the window and the frame but also pinching which occurs between the side edges of the window and the side frames thereof, which is something which may happen with the rear windows in many car models and may cause serious injury to persons but cannot be detected by the above-described systems owing to the limitations thereof. This situation has been amply described in publications and journals relating to the industry.
The gravity of the above-described situations has caused even the authorities of the European Union to publish appropriate standards to ensure that the force with which the automatic windows are raised does not exceed critical values since, if this is not the case, such windows may cause very serious injuries to fingers, arms, the neck and other parts of the body which may become trapped between the upper or side edges of the window and those of the door frames or structures covering the latter.